Preheat oven 350F (175 C)
Grease 9 inch round baking pan
Drain and rinse the beans and put in food processor with the eggs. Blend until smooth.
Add the sugar and baking powder. Pulse to mix.
Put chocolate chips in microwave safe bowl and heat for a minute. Mix and then keep heating 20 seconds and mixing until chocolate is melted. If microwave is strong, cut power to 50%.
Pour melted chocolate in food processor and blend until thouroughly mixed. You may have to scrape sides with spatula a couple of times.
Pour mix into greased pan and bake for 40 minutes or until knife comes out clear. ( I baked mine for 35 mins.)
Allow to cool in pan or on rack for 15 - 20 mins. Invert on plate and sprinkle powdered sugar over top if desired.